{"id":2042,"date":"2023-03-31T17:59:47","date_gmt":"2023-03-31T23:59:47","guid":{"rendered":"https:\/\/www.ntotank.com\/blog\/?p=2042"},"modified":"2024-01-23T18:38:50","modified_gmt":"2024-01-24T00:38:50","slug":"proper-sodium-hypochlorite-storage-in-polyethylene-tanks","status":"publish","type":"post","link":"https:\/\/ntotank.com\/blog\/proper-sodium-hypochlorite-storage-in-polyethylene-tanks","title":{"rendered":"Chemical Tanks | Proper Sodium Hypochlorite Storage in Polyethylene Tanks"},"content":{"rendered":"\n
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Guide to Maximizing Bleach and Bleach Tank Service Life<\/h2>\n\n\n\n

Sodium hypochlorite (bleach, NaOCl<\/em>) is a strong oxidizing agent with various breakdown concerns that present specific considerations for the proper storage of this widely used chemical solution. Bleach is defined as a hazardous chemical by the U.S. EPA<\/a>, and one that is capable of corrosive damage to person and material, particularly at high concentrations. Therefore, the right storage and handling requirements are important to maximize safety as well as the service life of both the bleach solution and its container. <\/p>\n\n\n\n

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In North America, sodium hypochlorite is frequently stored, used, and distributed within polyethylene plastic tanks and IBC totes. Bleach is commonly kept for use as a whitening agent, for sanitization, or to drive a variety of chemical reactions. The solution has extensive use in the food industry, healthcare, and in drinking water, wastewater, and water management systems. <\/p>\n\n\n\n

Under the right conditions, polyethylene tanks can provide up to and potentially beyond 10 years of safe use. To achieve these results, it is necessary to follow the right storage guidelines that take into account NaOCl\u2019s unique chemical characteristics and properties.<\/p>\n\n\n\n

In this Chemical Tanks Series, we will cover six main points on how to effectively and safely store sodium hypochlorite in polyethylene tanks to achieve long-term, successful results.<\/p>\n\n\n\n

6 Points on How to Properly Store Bleach in Polyethylene<\/h2>\n\n\n\n

1) Use HDPE, Not Other Polyethylene Variants<\/h3>\n\n\n\n

Polyethylene is a synthetic material, i.e., plastic, that is engineered into various forms. The most common are high density, low density and cross linked polyethylene; abbreviated HDPE, LDPE and XLPE, respectively. These polyethylene variants differ in their manufacture and their resulting properties, meaning each can be better suited for certain chemical storage applications. In bleach storage, studies have demonstrated HDPE is more durable<\/a> and with greater total resistance against NaOCl damage than the other poly types, particularly XLPE. Therefore, when selecting a poly bleach tank, choose HDPE. <\/p>\n\n\n\n

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High density poly tanks are acceptable for \u2264 16.5% NaOCl solutions kept beneath 100\u00b0F and at atmospheric pressure. HDPE bleach storage tanks<\/a> should be manufactured to 1.9 specific gravity (SG<\/em>) according to ASTM D-1988 to 600 PSI hoop stress standards. Bleach is well suited for storage in HDPE tanks up to 12,500 gallons in vertical style tanks, horizontal tanks, cone bottom tanks, and double walled containment tanks.<\/p>\n\n\n\n

The service life of a poly bleach tank falls between 3 to 12 years. This wide range is due to the number of variables involved in NaOCl storage, proper care and maintenance as well as workmanship of the poly tank brand. This therefore makes it important to select quality tank manufacturers<\/a> and store bleach under ideal conditions. HDPE tanks are also capable of thermoplastic welding, while XLPE is not, allowing for tank repair when needed; a further benefit should the work case require.<\/p>\n\n\n\n

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2) Protect From Sunlight Ultraviolet (UV) Radiation<\/h3>\n\n\n\n

Storing bleach in polyethylene tanks can leave solutions susceptible to decomposition reactions resulting from UV sun exposure unless preventive actions are taken. UV rays can penetrate an unprotected polyethylene tank and reach the molecular NaOCl structure where an energy transfer occurs that causes NaOCl molecules to react. The reaction produces oxygen gas, O2<\/sub>, and leaves behind sodium chloride, NaCl, water, and sodium chlorate, NaClO3<\/sub>, an undesired impurity. <\/p>\n\n\n\n

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The UV to bleach interaction is a chemical breakdown that reduces bleach concentration, solution purity, and therefore the chemical’s relative effectiveness. The oxygen gas produced is a potential safety hazard. Extensive oxygen buildup can cause a tank to rupture if left unchecked and unmitigated under scenarios of high concentrations, extended UV exposure, and bleach decomposition.<\/p>\n\n\n\n

Note the following conditions on how to best protect a poly bleach tank from sunlight UV effects:<\/p>\n\n\n\n